Pneumatic pressure regulating valve

ABSTRACT

A pneumatic pressure regulating valve, the opening of which can be automatically changed in a pressure-related manner, including a control diaphragm that is subjected to a reference pressure, to the gas pressure as well as to a governor spring, wherein a change in the differential pressure causes an adjustment of the control diaphragm and the latter itself or a closing element actuated by it changes the opening through an outflow cross-section, and wherein a structure that is arranged adjacent to the outflow cross-section on the diaphragm side forms a stop for the control diaphragm or for the closing element in the closed position of said control diaphragm. At least one preliminary stop is arranged in the pressure regulating valve such that, when the control diaphragm is moving in its closing direction, the control diaphragm or the closing element first comes into contact with the preliminary stop and that, when the control diaphragm is moving further in its closing direction, the control diaphragm or the closing element will then, while being subjected to elastic and flexible deformation or being further subjected to elastic and flexible deformation respectively, further reduces the opening and, in a final position, also comes into contact with the stop.

PRIORITY CLAIM

This application is a divisional application of application Ser. No.10/592,697, filed Sep. 11, 2006, which was the National Stage ofInternational Application No. PCT/EP2005/002587, filed Mar. 11, 2005,designating the United States.

BACKGROUND OF THE INVENTION

The present invention relates to a pneumatic pressure regulating valvearranged in the path of a gas line, the opening of which can beautomatically changed by means of said pressure regulating valve inrelation to the differential pressure between a reference pressure andone or more gas pressures applied to at least one inlet of saidregulating valve, wherein a control diaphragm is provided in thepressure regulating valve, said control diaphragm being, on the onehand, subjected to the reference pressure and, on the other hand, to thegas pressure or gas pressures as well as to a governor spring, wherein achange in the differential pressure between the regions adjacent to thecontrol diaphragm causes an adjustment of the control diaphragm and thecontrol diaphragm itself or a closing element actuated by the controldiaphragm increases or reduces the opening through an outflowcross-section of the pressure regulating valve, and wherein a structureof the pressure regulating valve that is arranged adjacent to theoutflow cross-section on the diaphragm side forms a stop for the controldiaphragm or for the closing element actuated by the control diaphragmin the latter's closed position.

A pneumatic pressure regulating valve designed as a throttle valve forautomatically controlling the pressure in the crankcase of an internalcombustion engine and comprising the elements mentioned above has beendisclosed in DE 200 16 214 U1. This known throttle valve is providedsuch that it comprises two power elements for generating the returnforce acting on the control diaphragm, wherein a first power elementexerts its return force on the control diaphragm over the entire traveldistance of said control diaphragm, and wherein a second power elementexerts its return force on the control diaphragm only over the secondsection of the travel distance of said control diaphragm, wherein saidsecond section of the travel distance is the distance between apartially open position and the closed position of said controldiaphragm. It is, furthermore, preferably provided that the two powerelements are formed by two springs, the first of which is in permanentoperable engagement with the control diaphragm and the second of whichenters into operable engagement with the control diaphragm only after afirst section of the travel distance of the control diaphragm has beencovered in closing direction. Preferably, the two springs are helicalsprings of varying length.

This known throttle valve is considered to be to disadvantage in thatthe use of two springs requires a further spring which has to bemanufactured and installed in addition. In this case, a higher number ofcomponents and increased manufacturing and assembling efforts, thus,have to be paid for the improved control characteristic achieved bymeans of the two power elements. What is more, this known throttle valveis to disadvantage in that the tolerances of the various components,here the springs, are adding up, with the result that the overallarrangement is more imprecise.

An alternative executive form of said known throttle valve according toDE 200 16 214 U1 provides that one power element is formed by a springand that the other power element is the control diaphragm itself, saidcontrol diaphragm being provided with its own return force or with anintegrated power element. While it is true that this prevents therequirement of a separate second spring, it has turned out that it isdifficult to produce the control diaphragms which are suitable for thisexecutive form of the valve and comprise their own exactly defined andpermanently constant return force or an appropriately acting integratedpower element.

A third version of this known throttle valve comprises instead of thetwo power elements one power element that exerts at least two differentreturn forces and exerts a first return force on the control diaphragmover a first section of the travel distance of said control diaphragmand exerts a second higher return force on the control diaphragm over asecond section of the travel distance of said control diaphragm.Theoretically, this executive form is a more elegant solution because itrequires only one power element, but it has, here as well, turned out tobe difficult to reproducibly manufacture such a power element andintegrate it in the throttle valve, said power element having two returnforces which are different in their relation to the travel distance.

SUMMARY OF THE INVENTION

Therefore, the present invention aims at creating a pneumatic pressureregulating valve of the aforementioned type, which obviates thedrawbacks disclosed and which can, in particular, be used to achieve areliable and permanently uniform function as well as a good controlcharacteristic while, at the same time, having a simple design andwhich, over and above this, can provide the option of separating liquidsfrom the gas flow passing through the pressure regulating valve.

This problem is solved by the invention by means of a pneumatic pressureregulating valve of the aforementioned type which is characterized inthat at least one preliminary stop is arranged in the pressureregulating valve such that, when the control diaphragm is moving in itsclosing direction, the control diaphragm or the closing element actuatedby the control diaphragm first comes into contact with the preliminarystop and that, when the control diaphragm is moving further in itsclosing direction, the control diaphragm or the closing element actuatedby the control diaphragm, while being subjected to elastic and flexibledeformation or being further subjected to elastic and flexibledeformation respectively, further reduces the opening and, in a finalposition, also comes into contact with the stop.

This pressure regulating valve is to advantage in that it does notrequire any additional spring nor any other additional power element.Instead, it suffices to arrange at least one preliminary stop in thepressure regulating valve, said preliminary stop being associated withthe control diaphragm in the way and manner mentioned. In its movementsprior to any contact with the preliminary stop, the control diaphragm inthe pressure regulating valve according to the invention behaves likethe control diaphragm in a conventional pressure regulating valve. Afterthe control diaphragm has come into contact with the preliminary stop,the further movement of the control diaphragm is performed subject to adifferent characteristic which has been caused and influenced by thepreliminary stop, thereby achieving the desired improved controlcharacteristic of the pressure regulating valve. The change of thecharacteristic in the adjustment of the control diaphragm depends on theproperties of the control diaphragm, on the spacing between thepreliminary stop and the actual stop for the final position or closedposition of the control diaphragm, and on the design of the preliminarystop. By altering the properties of the control diaphragm and/or thespacing between the preliminary stop and the stop and/or the design ofthe preliminary stop, the control characteristic can be manipulated in asimple manner. Since any additional moving components are not requiredfor achieving this function, the pressure regulating valve according tothe invention is not subject to any additional sources of wear and tear.What is more, the integration of a preliminary stop in the pressureregulating valve requires only little additional effort, which does notresult in any rise in the cost of manufacture of the pressure regulatingvalve and its parts. Thus, the pressure regulating valve according tothe invention allows to achieve the desired enhancement of the controlcharacteristic in a manner that is particularly simple from a technicalview and, hence, also particularly cost-effective, wherein it is, at thesame time, also possible to easily modify and optimize the controlcharacteristic.

In a further embodiment, it is preferably provided that the controldiaphragm is an elastomeric diaphragm and/or that the closing element isan elastomeric element or comprises an elastomeric lining. On the onehand, the use of an elastomer for the control diaphragm and/or theclosing element guarantees the desired elastic and flexible propertiesand, on the other hand, it ensures a sensitive response and also a longservice life of the pressure regulating valve.

A further embodiment provides that the preliminary stop is designedand/or retained in an elastic and flexible manner. In this executiveform, the elasticity and flexibility of the control diaphragm issuperimposed by an elasticity and flexibility of the preliminary stop,thereby allowing further manipulation and optimization of the controlcharacteristic of the pressure regulating valve.

One solution, the technical requirements for which are particularly low,provides that the preliminary stop is formed by at least one pin whichis arranged in, preferably concentrically to the stop. The pin can beinstalled in the stop, which is usually formed by a pipe connectionpiece, without difficulty, wherein it is possible to form said pinintegrally with said stop or to insert said pin subsequently, e.g. byscrewing, gluing, or welding.

As an alternative, the preliminary stop can be formed by a circle ofpins arranged in a radially outward direction from, preferablyconcentrically to the stop. Here as well, the integration of thepreliminary stop in the pressure regulating valve requires only littlemanufacturing efforts.

A further alternative embodiment provides that the preliminary stop isarranged in a radially outward direction from the stop and is designedin the form of a ring or ring segment, preferably concentrically to saidstop.

For the purpose of a simple manufacture of the pressure regulatingvalve, it is, furthermore, preferably provided that the preliminary stopis connected to or formed integrally with a casing of the pressureregulating valve.

In order to ensure that the control diaphragm in the pressure regulatingvalve according to the invention comprises as long a service life aspossible under the loads occurring, it is proposed to reinforce thecontrol diaphragm with a diaphragm supporting body. Therein, thediaphragm supporting body is, appropriately, made of a material that isstiffer than the material of the remaining control diaphragm, in orderto achieve a desired reinforcing effect in specific selectable regionsof the control diaphragm.

For this purpose, a first further development provides that thediaphragm supporting body is a prefabricated component part and that theremaining control diaphragm is molded around the diaphragm supportingbody. In this manner, it is ensured that the connection of the diaphragmsupporting body to the remaining control diaphragm is particularly firm.

An alternative embodiment thereto provides that the diaphragm supportingbody is a prefabricated component part and that it is connected,particularly buttoned or engaged to the control diaphragm on the side ofthe governor spring or that it is loose and pressed onto the controldiaphragm by means of and on the side of the governor spring. Themanufacture of this embodiment is simpler and, thus, morecost-effective.

In order to provide additional possibilities of selectively manipulatingand modifying the control characteristic of the pressure regulatingvalve, it is furthermore proposed that one or more elements are formedto fit to or are attached to the control diaphragm side facing the stop,said elements cooperating with the preliminary stop.

In a preferred further development, the above-mentioned elements areprojections formed integrally with or connected to the diaphragmsupporting body. The diaphragm supporting body can be subjected to ahigher mechanical load than the remaining diaphragm, so that thecooperation of the elements forming a part of the diaphragm supportingbody with the preliminary stop do not have any effects on the controldiaphragm that reduce the latter's service life.

An alternative measure for creating possibilities of manipulating thecontrol characteristic of the pressure regulating valve and forpreserving the control diaphragm is to design the region of the surfaceof the control diaphragm or the closing element that cooperates with thepreliminary stop with a thickening or a lining or an insert.

In order to achieve a desired control characteristic, it may, as analternative and instead of reinforcing or stiffening the controldiaphragm in certain regions, also be reasonable to reduce the thicknessor weaken the material of the control diaphragm or the closing elementin that region of its surface that cooperates with the preliminary stop.

It is also possible to use the preliminary stop for manipulating thecontrol characteristic of the pressure regulating valve in the way andmanner desired. To achieve this, it is particularly provided that thepreliminary stop is rounded or lenticular or spherical or conical orstepped on its front face.

In the region between the stop on the one hand and the control diaphragmor valve body on the other hand, the gas flow undergoes a relativelysharp change in its direction, in particular if the pressure regulatingvalve is only partially open. In order to achieve a favorablemanipulation of the flow conditions in this case, one embodimentprovides that the pin arranged in the stop is designed with adiminishing outside diameter, as seen in the direction of the gas flowthrough the stop. Herein, the contour of the pin may, for example,extend in the shape of a cone or a trumpet, so as to produce an improvedflow path.

In order to avoid malfunctions of the pressure regulating valve causedby the control diaphragm adhering or sticking to the preliminary stopand/or the stop as well as to prevent premature wear and tear of thecontrol diaphragm, a further embodiment of the pressure regulating valveproposes that the preliminary stop and/or the stop and/or the region ofthe surface of the control diaphragm that cooperates with thepreliminary stop and/or the stop are/is provided with an anti-sticklining and/or an anti-abrasion layer.

A particularly cost-effective manufacture of the pressure regulatingvalve is provided by an executive form where the casing including stopand preliminary stop is a one-piece injection-molded part of plastic ora one-piece die casting of light metal. In this executive form, thecasing including stop and preliminary stop can be manufactured inout-of-tool production so that the step of integrating the additionalpreliminary stop in the casing does not require any additionalmanufacturing efforts and needs only a minimum of additional plastic orlight metal material.

A pressure regulating valve as has been described and illustrated abovecan be advantageously utilized for various applications. The pressureregulating valve according to the invention can be used to particularadvantage if it is a crankcase pressure regulating valve for regulatingthe gas pressure in the crankcase of an internal combustion engine andif, therein, the pressure regulating valve is arranged in the path of acrankcase ventilation line. A favorable control characteristic that canbe selectively manipulated and optimized is of particular importance insuch a crankcase pressure regulation valve application, in order toensure troublefree and smooth operation of an associated internalcombustion engine.

The pressure regulating valve further contributes to a cost-effectivemanufacture in that, in a preferred embodiment, the pressure regulatingvalve, together with further components of the internal combustionengine, is arranged in a module that can be connected to the internalcombustion engine. This also permits to achieve a particularlyspace-saving construction and a particularly easy assembly when thecomponents pertaining to an internal combustion engine are attachedthereto.

To this end, a practical further development preferably proposes thatthe further components of the module are devices for separating oil mistfrom the crankcase ventilation gas of the internal combustion engineand/or for filtering lubricating oil and/or fuel of the internalcombustion engine. This is to advantage in that the flow paths for thecrankcase ventilation gas are short with regard to oil-mist separation.Moreover, the parts having to be maintained or replaced at regularintervals, in particular filter elements, are, thus, arranged in aconcentrated and easily accessible manner.

According to the invention, it is, furthermore, preferably provided thatthe pressure regulating valve or the module comprising the pressureregulating valve is integrated in a cylinder head cover of the internalcombustion engine. In addition to the benefit of a compact construction,this is to additional advantage in that short paths are sufficient forventilating the crankcase, thus being to advantage for the properfunction of the pressure regulating valve and the internal combustionengine as a whole.

A further embodiment of the pneumatic pressure regulating valveaccording to the invention is characterized in that the preliminary stopis formed by at least one preliminary stop structure that is positionedin the outflow cross-section and is flat and perforated on the side ofthe diaphragm or closing element.

This flat and perforated structure of the preliminary stop allows tocreate a structure against which the control diaphragm or closingelement, when moving in its closing direction, bears in an increasingmanner, that is while it progressively covers the surface of saidstructure. As the vacuum pressure on the outflow side of the pressureregulating valve increases, the vacuum pressures on the controldiaphragm projection area arranged opposite to the outflow cross-sectionare also high, in particular when the output mass flow rates through thepressure regulating valve are low. While the control diaphragm isincreasingly bearing against the preliminary stop structure, the freeforces acting in the closing direction of the control diaphragm are,accordingly, decreasing steadily. This effect is produced by the factthat the forces acting in the closing direction of the control diaphragmare directly supported against the casing of the pressure regulatingvalve in those regions of the control diaphragm where the latter alreadybears against the preliminary stop structure via said preliminary stopstructure. In this manner, any undesired premature closing of thepressure regulating valve is prevented with low technical requirements.At the same time, a desired valve characteristic of the pressureregulating valve, which is largely independent of the particular vacuumpressure on the outflow side, is achieved for the pressure on the inflowside. If the pressure regulating valve is used for regulating thepressure in the crankcase of an internal combustion engine, this ensuresa good ventilation of the crankcase over the entire characteristicengine map. Owing to the advantageous control characteristic of thepressure regulating valve over the entire characteristic map of theinternal combustion engine, the pressure in the crankcase can be set toa value just below the atmospheric pressure; for that reason, thedifferential pressure that can be utilized for oil-mist separation is,at the same time, comparably higher, with the result that the separationcapacity is also higher. When having the same dimensions as aconventional pressure regulating valve, the pressure regulating valveaccording to the invention has a clearly better characteristic curve.Alternatively, the pressure regulating valve can be reduced in size,with the result that the characteristic curve of the valve is still ofthe same quality as that of a larger conventional pressure regulatingvalve. This is also to advantage in that proven component parts, inparticular the diaphragm, can still be used when the physical size ismaintained.

In order to simplify the manufacture of the pressure regulating valveand to save assembly steps, a further development of the pressureregulating valve provides that the preliminary stop structure is formedintegrally with the structure of the pressure regulating valve thatforms the stop.

As an alternative, it is proposed that the preliminary stop structure isdesigned in the form of one or more component parts and is connected tothe structure of the pressure regulating valve that forms the stop.Although this executive form requires a little more assembly steps, thefreedom with regard to design and material selection for the preliminarystop structure is considerably higher.

It is, furthermore, preferably provided that the control diaphragm orthe closing element actuated by the control diaphragm has a convex shapeon its side facing the preliminary stop structure or can be deformed tobe convex when a differential pressure is applied. The convex shapeensures that the control diaphragm or the closing element initiallybears against the preliminary stop structure in its central region,while the control diaphragm or the closing element moves in the closingdirection of the pressure regulating valve. While the control diaphragmor the closing element further moves in said closing direction, thesurface bearing against the preliminary stop structure steadilyincreases in size, wherein said surface is increased from withinoutward, as seen in radial direction. The control diaphragm or theclosing element may comprise the convex shape as a permanently givenshape; as an alternative, it is also possible for the desired convexshape to develop only if the appropriate pressure conditions areexisting, before the control diaphragm or the closing element reachesits first abutment against the preliminary stop structure.

Since, in the pressure regulating valve according to the invention, aflexibility of the control diaphragm is not only not disturbing, buteven advantageous, the control diaphragm is preferably an elastomericdiaphragm, which is free from any supporting body at least in its regioncooperating with the preliminary stop structure. Such a diaphragm is, inaddition, to advantage in that it can be manufactured easily if asupporting body does not exist.

In a further embodiment, it is provided that the preliminary stopstructure is flat on its side facing the control diaphragm or theclosing element. In this executive form, the preliminary stop structureis particularly simple in its geometry. In association with a convexlyshaped surface of the control diaphragm or closing element, however, aflat preliminary stop structure also allows to achieve the desiredeffect of a steadily increasing abutment of the control diaphragm or theclosing element to the preliminary stop structure when the valve isadjusted in its closing direction.

As an alternative, it is also possible that the preliminary stopstructure is convex on its side facing the control diaphragm or theclosing element. In this convex design of the stop structure, thedesired effect described above is achieved even in cooperation with aflat surface of the control diaphragm or closing element. The convexpreliminary stop structure can also cooperate with a convex surface ofthe control diaphragm or closing element. By selecting the designs andby means of the measure of the convexity as well as the thickness or theflexibility of the diaphragm in the region facing the preliminary stop,the valve characteristic can be manipulated and optimized within a widerange and in the manner desired.

A further advantageous embodiment of the pressure regulating valveaccording to the invention provides that the preliminary stop structureextends into the structure forming the stop in axial direction of saidstructure. In axial direction of the structure forming the stop for theclosed position of the valve, the preliminary stop structure, hence,forms flow paths which are, in essence, extending perpendicularly to thesurface of the preliminary stop structure. Particularly when thepressure regulating valve is partially closed, that is when the controldiaphragm is positioned very closely to the preliminary stop structureor is already partially bearing against the preliminary stop structureor when the closing element is positioned appropriately, the gas flow,on entering into the breakthroughs of the preliminary stop structure,undergoes a very sharp change in direction. In association with a highgas flow rate, which is inevitably developing because of the reducedflow cross-section, this redirection results in a centrifugal separationof liquid droplets carried along in the flow, for example oil dropletsforming an oil mist carried along in the gas flow. Since the preliminarystop structure extends into the structure forming the stop in axialdirection, there is a high probability that liquid droplets carriedalong in the gas flow impinge and settle on one of the surfacesdelimiting the preliminary stop structure. If the pressure regulatingvalve is accordingly arranged and aligned in space, the fluid settled inthe preliminary stop structure can be discharged in the direction of theoutlet by virtue of gravity and/or due to the effect of the gas flow.Downstream of the preliminary stop structure, as seen in flow direction,the cleaned gas can then be discharged from the pressure regulatingvalve by an appropriate flow path, independently of the separated fluid.If the preliminary stop structure is designed appropriately, it ispossible to achieve separation efficiencies which correspond to theseparation efficiencies of conventional independent liquid separatorsfor gas flows to an approximate or even a very large extent.

This is, moreover, to advantage in that, by combining pressureregulation with oil-mist separation and by adjusting the gap between thediaphragm and the preliminary stop, the highest possible gas velocitiescan be reached largely independently of the extent of the gas volumeflow of oil-mist separation.

In order to achieve a distinct liquid separation from the gas flowinside the pressure regulating valve, the length of the axial extensionof the preliminary stop structure preferably amounts to at least 25percent of a clear inside diameter of the structure forming the stop.

In order to achieve a particularly high efficiency in the separation ofliquid droplets from the gas flow, it is, furthermore, preferablyprovided that the length of the axial extension of the preliminary stopstructure amounts to 50 percent up to more than 100 percent of the clearinside diameter of the structure.

The fact that the breakthroughs in the preliminary stop structure eachpreferably comprise an axial length that is great in relation to therespective clear diameter of the breakthroughs further contributes toachieving a high separation efficiency.

In a further embodiment, it is proposed that the breakthroughs in thepreliminary stop structure each comprise an axial length that is atleast five times as great as the clear diameter of the particularbreakthroughs.

If a particularly high separation efficiency is aimed at, it ispreferably provided that the breakthroughs in the preliminary stopstructure each comprise an axial length that is ten to twenty times asgreat as the clear diameter of the particular breakthroughs. With suchratios of length to diameter, it is, with a high probability, ensuredthat the liquid droplets carried along in the gas flow cannot runthrough the preliminary stop structure without settling on one of thesurfaces of the preliminary stop structure.

A further increase in separation can be achieved if the breakthroughs inthe preliminary stop structure do not extend linearly in their axialdirection, but if the duct extends such that the outlet openingcomprises an offset as compared with the inlet opening.

In order to ensure that, on the one hand, the preliminary stop structuredoes not reduce the flow cross-section through the pressure regulatingvalve to an impermissible degree and that, on the other hand, thepreliminary stop structure can be manufactured with an appropriatemechanical stability and the diaphragm is not damaged by repeatedlycontacting the preliminary stop structure, it is preferably providedthat the breakthroughs in the preliminary stop structure comprise anoverall surface ranging from 20 percent to 80 percent of the overallsurface of the structure forming the stop.

The pressure regulating valve according to the invention allows a highdegree of freedom with regard to the design of the structure forming thestop and the preliminary stop structure provided therein. The structureforming the stop and the preliminary stop structure provided thereinpreferably have a circular, elliptical, oval, ovoid, or polygonal outercontour outline. By varying and appropriately selecting the contouroutline, the behavior of the pressure regulating valve can be changed,whereby it is possible to manipulate the valve characteristic in themanner desired.

The preliminary stop structure as such can also be designed in manifoldways with regard to its form. A first preferred executive form providesthat the preliminary stop structure has the form of a lattice of flatand plane walls that are intersecting each other or of radial andconcentric walls that are intersecting each other. Owing to theintersecting walls, the preliminary stop valve has a particularly highmechanical stability, thus even allowing mobile applications, forexample on an internal combustion engine of a motor vehicle, without anydamage.

In an alternative embodiment, it is proposed that the preliminary stopstructure has the form of a grating of flat and plane walls extending inparallel to each other or of walls extending concentrically to eachother. This embodiment is to advantage in that the walls occupy asmaller cross-sectional area and a smaller volume within the preliminarystop structure, thus providing as large a flow cross-section as possiblewith given dimensions of the structure forming the stop.

A particularly large free flow cross-section with given dimensions ofthe structure forming the stop is achieved if, according to a furtherembodiment, the preliminary stop structure has the form of a corrugated,layered or wound honeycomb. Honeycombs are, for example, known as suchfrom catalyst technology where large flow cross-sections are required inconnection with large surfaces; this design is also of benefit to theeffective liquid separation in the preliminary stop structure desired inthe present invention.

A further possible design to be mentioned provides that the preliminarystop structure can have the form of a bed of a plurality of parallellongitudinal pins or segments that are spaced apart from each other andthe free ends of which are facing the control diaphragm or the closingelement. With this embodiment, it can also be ensured that more than 50percent of the cross-section of the preliminary stop structure isavailable for the gas flow. At the same time, however, the desired flatdesign in the region of the free ends of the pins or segments ispreserved in order to allow the control diaphragm or the closing elementto bear against the surface of the preliminary stop structure in asteadily progressive manner.

The freedom of designing the cross-section of the breakthroughs in thepreliminary stop structure is also very wide-ranging. preferably, thebreakthroughs each have a cross-section that is circular, elliptical,oval, polygonal or slotted or have the shape of a circular sector orcircular-ring sector.

A further embodiment of the pressure regulating valve provides that thebreakthroughs in the preliminary stop structure all have the samecross-section.

As an alternative, the breakthroughs in the preliminary stop structurecan comprise at least two different cross-sections. This creates afurther possibility of manipulating the control characteristic and thevalve characteristic.

To achieve this, a physical further development proposes that thebreakthroughs in the preliminary stop structure are greater on theirinside and smaller on their outside, as seen in the radial direction ofsaid breakthroughs. This embodiment is to particular advantage in that,especially with a particularly small opening cross-section, that is whenthe control diaphragm or the closing element is positioned near itsclosed position, the pressure is still regulated in a sensitive manner.

If it is not the control diaphragm itself that cooperates with thepreliminary stop and the stop within the pressure regulating valve, butthe closing element actuated by said control diaphragm, it isappropriate that the closing element carries on its side facing thepreliminary stop structure a lining that is elastic and flexible and/orcompressible in axial direction. By using this lining, the remainingparts of the closing element can be made of a stable and rigid material,so that said closing element can transfer the movements performed by thecontrol diaphragm without any falsification.

In order to prevent the liquid separated from the gas flow in thepressure regulating valve from re-entering into the gas flow carriedaway from the pressure regulating valve in an undesired manner, it isappropriately provided that the pressure regulating valve is designedwith a liquid collection chamber on its outlet side, wherein at leastthe liquid separated from the gas flow flowing through the pressureregulating valve at the preliminary stop structure can be collected in aliquid collection region.

By arranging internal attachments, such as partition walls or flow guidewalls, in the liquid collection region, any formation of waves orso-called splashing of the liquid separated, caused by the accelerationsacting on the liquid column, can be suppressed. preferably, these wallscan be designed in the form of a lattice or arranged concentrically andcomprise a cross-section having the shape of a circle or circle segment.

Furthermore, staggered breakthroughs allowing a uniform distribution ofthe liquid in the liquid collection region can be provided in thepartition walls. As an alternative, open-cellular spongy structures canbe used there.

In order to be able to separate liquid from the gas flow within thepressure regulating valve, in addition or as an alternative to theliquid separation in the preliminary stop structure, a furtherembodiment of the pressure regulating valve provides that the liquidcollection chamber is designed as a vortex chamber that is circular incross-section and that forms a separator in which liquid droplets stillcontained in the gas flow through the pressure regulating valvedownstream of the preliminary stop structure can be separated from saidgas flow by centrifugal force.

A further embodiment in respect thereto provides that the part of theliquid collection chamber that is at the top when the latter is in itsinstallation position is designed as a cyclone with a tangential gasinlet, with a cleaned-gas outlet outgoing towards the top both centrallyand axially, and with a liquid outlet going down and ending in theliquid collection region positioned underneath the cyclone. In thisembodiment of the pressure regulating valve, a cyclone separator isintegrated therein, said cyclone separator ensuring an effectiveseparation or subsequent separation of liquid, particularly in the formof fine droplets, from the gas flow.

As has been mentioned above, the liquid separated is preferablycollected in a liquid collection region. From there, the collectedliquid can be disposed as required according to the volume collected,for example in the course of regular maintenance measures.

As an alternative, the liquid collection region can be connected to aliquid discharge line or liquid return line via a valve, preferably viaa check valve that is controlled by differential pressure, such as areed valve. This solution permits to automatically drain the fluidcollection region, which is performed whenever the existing pressureconditions are suitable for draining. If, for example, the pressureregulating valve is used as a crankcase pressure regulating valve on aninternal combustion engine, the liquid collection region, which willthen be an oil collection region, can be drained whenever the associatedinternal combustion engine is at standstill, wherein the collected oilis, appropriately, passed into the oil pan of the internal combustionengine.

In order to ensure reliable operation of the pressure regulating valveeven at low ambient temperatures, it is furthermore proposed that thepreliminary stop structure and/or the control diaphragm or the closingelement is provided with a heating device. The heating device can beused to ensure that the preliminary stop structure and/or the controldiaphragm or the closing element always comprise(s) such a hightemperature that liquid particles from the gas flow cannot freezethereto and that, thus, any freezing of the pressure regulation valveresulting therefrom is prevented as a whole.

A further measure for ensuring reliable operation of the pressureregulating valve is to arrange a preseparator, preferably an impingementseparator or a prescreen, capturing coarse oil droplets and/orcontaminants from the gas flow, upstream of the preliminary stopstructure as seen in the direction of the gas flow. The prescreenensures that coarse contaminants which would be able to block thebreakthroughs in the preliminary stop structure are prevented fromarriving there, but are captured beforehand instead. The impingementseparator allows to separate large-size oil droplets with little effort,so that said oil droplets do not affect proper functioning of thedownstream components.

Furthermore, it can be provided that the gas inlet in the lower chamberof the pressure regulating valve is arranged tangentially, so that theinflowing gas is caused to rotate. On entry into the breakthroughs ofthe preliminary stop structure, the translational and rotationalmovements of the gas and the oil droplets entrained therein superimposeeach other, thus increasing the probability that an oil droplet isseparated in the breakthroughs.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, exemplary embodiments of the pressure regulating valve accordingto the invention will be illustrated by means of a drawing, in which:

FIG. 1 is a cross-sectional view of a pressure regulating valve in afirst embodiment, in its open state;

FIG. 2 shows the pressure regulating valve of FIG. 1 in a partiallyclosed state;

FIG. 3 shows the pressure regulating valve of FIG. 1 and FIG. 2 in itscompletely closed state;

FIG. 4 shows the pressure regulating valve in a second embodiment, inits open state;

FIG. 5 shows the pressure regulating valve of FIG. 4 in a partiallyclosed state;

FIG. 6 shows the pressure regulating valve of FIG. 4 and FIG. 5 in itscompletely closed state;

FIG. 6 a is a bottom view of a diaphragm of the pressure regulatingvalve according to FIGS. 4 to 6;

FIG. 7 shows the pressure regulating valve in a third embodiment, in itsopen state;

FIG. 8 shows the pressure regulating valve of FIG. 7 in a partiallyclosed state;

FIG. 9 shows the pressure regulating valve of FIG. 7 and FIG. 8 in itscompletely closed state;

FIG. 10 shows the pressure regulating valve in a forth embodiment, inits open state;

FIG. 11 shows the pressure regulating valve of FIG. 10 in a partiallyclosed state;

FIG. 12 shows the pressure regulating valve of FIG. 10 and FIG. 11 inits completely closed state;

FIG. 13 shows the pressure regulating valve in a fifth embodiment, inits open state;

FIG. 14 shows the pressure regulating valve of FIG. 13 in a partiallyclosed state;

FIG. 15 shows the pressure regulating valve of FIG. 13 and FIG. 14 inits completely closed state;

FIG. 16 shows a pressure diagram for a conventional pressure regulatingvalve as compared with a pressure regulating valve according to theinvention;

FIG. 17 shows the pressure regulating valve in a sixth embodiment, inits open state;

FIG. 18 shows the pressure regulating valve in a seventh embodiment, inits open state;

FIG. 19 shows the pressure in an eighth embodiment, in a partiallyclosed state;

FIG. 20 shows the pressure regulating valve in a ninth embodiment, in apartially closed state;

FIG. 21 shows the pressure regulating valve in a tenth embodiment, in apartially closed state;

FIG. 22 shows the pressure regulating valve in an eleventh embodiment,in a partially closed state;

FIG. 23 is a longitudinal sectional view of the pressure regulatingvalve in a further embodiment;

FIG. 23 a to FIG. 23 d each show a detail of the pressure regulatingvalve in four different operating states;

FIG. 24 is a longitudinal sectional view of a further pressureregulating valve;

FIG. 24 a is a longitudinal sectional view of an enlarged detail of thepressure regulating valve according to FIG. 24;

FIG. 25 is a longitudinal sectional view of an outflow cross-sectiontogether with a preliminary stop as a part of a pressure regulatingvalve;

FIG. 25 a to FIG. 25 d each are top views of four different preliminarystops;

FIG. 26 a to FIG. 26 d each are top views of four further differentpreliminary stops;

FIG. 27 shows an outflow cross-section with a modified preliminary stop,in the same type of representation as in FIG. 25;

FIG. 27 a and FIG. 27 b each are top views of two further differentpreliminary stops;

FIG. 27 c shows an outflow cross-section with a modified preliminarystop, in the same type of representation as in FIG. 27;

FIG. 28 a is a longitudinal sectional view of a further outflowcross-section with a further preliminary stop;

FIG. 28 b is a top view of the outflow cross-section and the preliminarystop according to FIG. 28 a;

FIG. 29 a is a longitudinal sectional view of a further outflowcross-section with a preliminary stop;

FIG. 29 b is a top view of the outflow cross-section and the preliminarystop of FIG. 29 a;

FIG. 30 is a longitudinal sectional view of a closing element togetherwith a section of an outflow cross-section with a preliminary stop;

FIG. 30 a is a longitudinal sectional view of a closing element that ismodified as compared with FIG. 30;

FIG. 31 a is a longitudinal sectional view of a further pressureregulating valve together with a liquid collection chamber;

FIG. 31 b is a cross-sectional view of the pressure regulating valvetogether with the liquid collection chamber of FIG. 31 a;

FIG. 32 a is a longitudinal sectional view of a further pressureregulating valve with a liquid collection chamber;

FIG. 32 b is a cross-sectional view of the pressure regulating valvewith the liquid collection chamber of FIG. 32 a;

FIG. 33 a shows the pressure regulating valve with a longitudinalsectional view of a preseparator;

FIG. 33 b shows the pressure regulating valve with a cross-sectionalview of the preseparator;

FIG. 34 shows the pressure regulating valve with a longitudinalsectional view of a screen body;

FIG. 35 a and FIG. 35 b each are longitudinal sectional views of thepipe connection of the outflow cross-section together with a preliminarystop as a part of a pressure regulating valve;

FIG. 35 c and FIG. 35 d each are top views of preliminary stops of thepressure regulating valve; and

FIG. 36 shows a final variant of the pressure regulating valve with atangential gas inlet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a cross-sectional view of a pressure regulating valve 1. Thevalve 1 comprises a casing 10 that is closed with a cover 10′ on itsupper side. A control diaphragm 2 subdividing the inner region of thecasing 10 in a lower chamber 13 and an upper chamber 14 is fixed betweenthe casing 10 and the cover 10′. The upper chamber 14 is connected tothe atmosphere via a hole 14′ in the cover 10′, said hole 14′ having amatched cross-section.

The lower chamber 13 is connected to a gas inlet 11 in the form of alateral pipe connection piece. For example, the gas inlet 11 can beconnected to the crankcase ventilation line of an associated internalcombustion engine (not shown).

Furthermore, the lower chamber 14 is connected to a gas outlet 12 which,in the illustrated instance, points down and also has the form of a pipeconnection piece. For example, the gas outlet 12 can be connected to theintake section of an associated internal combustion engine.

With its upper part, the gas outlet 12 projects into the interior regionof the lower chamber 13, where it forms an outflow cross-section 3 inthe form of a short pipe connection piece 30. The upward pointing frontface of the pipe connection piece 30 forms a stop 31 for the controldiaphragm 2 as the latter moves down, that is toward the pipe connectionpiece 30.

A governor spring 5, here in the form of a helical compression spring,is arranged between a lower region of the casing 10 and the bottom sideof the control diaphragm 2, said lower region surrounding the pipeconnection piece 30. Said spring 5 subjects the control diaphragm to apreloading force acting in upward direction, that is in the openingdirection of the pressure regulating valve 1.

In its major part, the diaphragm 2 consists of an elastomeric body inwhich, here, a diaphragm supporting body 23 is inserted. Said diaphragmsupporting body 23 is, on the one hand, provided for stiffening thediaphragm 2 in the diaphragm region subjected to the governor spring 5.On the other hand, the diaphragm supporting body 23 comprises aplurality of projections that are protruding from the bottom side of thediaphragm 2 in downward direction and serve to guide and center thegovernor spring 5 in relation to the diaphragm 2.

In this pressure regulating valve 1, a pin 40 is furthermore arranged inthe pipe connection piece 30 concentrically thereto, wherein said pin 40is connected to or formed integrally with the internal perimeter of thepipe connection piece 30 via a plurality of connection blades 41extending in radial direction. The upper end of the pin 40 forms apreliminary stop 4 that protrudes in an upward direction beyond the stop31 that is formed at the upper end of the pipe connection piece 30.

FIG. 1 shows the pressure regulating valve 1 in its completely openposition. In this position, the maximum outflow cross-section 3 throughthe pipe connection piece 30 is available for the gas, for example thecrankcase ventilation gas, flowing through the pressure regulating valve1. The pressure regulating valve 1 enters this state if the vacuumpressure present in the lower chamber 13 is relatively low. In thisstate, the control diaphragm 2 is retained in its upper position, asshown in FIG. 1, by the governor spring 5.

FIG. 2 shows the pressure regulating valve 1 of FIG. 1, now in apartially closed position. Owing to a higher vacuum pressure in thelower chamber 13, which is caused by the differential pressure betweenthe two chambers 13, 14, the control diaphragm 2 is, in this state,displaced by a certain distance in downward direction, here to thatpoint where the bottom side of the diaphragm 2 bears against thepreliminary stop 4. Therein, the diaphragm 2 is deformed in an elasticand flexible manner, in particular in its radially outward marginalregion, wherein said diaphragm 2 is, at its fixing edge 20, retainedbetween the casing 10 and the cover 10′ in a sealing manner.

FIG. 3 shows the pressure regulating valve 1 of FIG. 1 and FIG. 2 in acompletely closed state. This state is achieved once the vacuum pressurepresent in the lower chamber 13 has increased further. The pressureregulating valve 1 can only reach its closed position, if, owing to thedifferential pressure between the lower and upper chambers 13, 14, thecontrol diaphragm 2 is also deforming in its central region 21, again inan elastic and flexible manner, until it has assumed the shape shown inFIG. 3. In this state, the bottom side of the diaphragm 2 bears not onlyagainst the preliminary stop 4, but also against the stop 31. As aresult, the outflow cross-section 3 is now completely closed.

In order to move the pressure regulating valve 1 from the stateaccording to FIG. 2 to its state according to FIG. 3, the controldiaphragm's 2 own return force, which is necessary to ensure that thediaphragm changes its shape from that shown in FIG. 2 to that shown inFIG. 3, must be overcome in addition to and at the same time with theforce of the governor spring 5. With the vacuum pressure in the lowerchamber 13 increasing and rising, this allows the pressure regulatingvalve to achieve a spring characteristic that is stronger than that atthe beginning of the adjusting movement of the diaphragm 2 where thelatter is only subjected to the governor spring 5. As a result, anypremature complete closing of the pressure regulating valve 1, which isundesired in many applications, can, in particular, be prevented withoutrequiring, for example, a second governor spring.

FIG. 4 shows a second version of the pressure regulating valve 1; thisversion corresponds to the executive form of the pressure regulatingvalve 1 according to FIGS. 1 to 3 in many parts. In contrast thereto,the pressure regulating valve 1 according to FIG. 4, however, isprovided with an insert 24 that is arranged centrally in the centralregion 21 on the bottom side of the diaphragm 2, said insert 24consisting of a material that is stronger and has a higher resistance towear than the elastomeric material of which the remaining diaphragm 2consists predominantly.

FIG. 5 shows the pressure regulating valve 1 of FIG. 4, now in apartially closed state. In this state, the control diaphragm 2 has moveddown to a point where the insert 24 at the bottom side of the diaphragm2 bears against the preliminary stop 4 at the upper end of the pin 40.Herein, the insert 24 ensures that the preliminary stop 4 does not causeany mechanical damage to the diaphragm 2 even in case of prolongedoperating times.

FIG. 6 shows the pressure regulating valve 1 of FIG. 4 and FIG. 5, nowin its completely closed state. In its central region 21, the diaphragm2 still bears against the preliminary stop 4 with its insert 24. In aradially outward direction from this insert 24, the central region 21 ofthe diaphragm 2 has moved down while being further deformed in anelastic and flexible manner, now also bearing against the stop 31 at theupper end of the pipe connection piece 30. Thus, the outflowcross-section 3 is now completely closed.

In its remaining parts, the pressure regulating valve 1 according toFIGS. 4 to 6 corresponds to the pressure regulating valve 1 according toFIGS. 1 to 3, for which reason reference is made to the description ofFIGS. 1 to 3, as regards the further component parts of the pressureregulating valve 1 according to FIGS. 4 to 6.

FIG. 6 a is a bottom view of the control diaphragm 2 of the pressureregulating valve 1 of FIGS. 4 to 6. The fixing edge 20 of the diaphragm2 is visible in outermost radial direction. The insert 24 thatcooperates with the preliminary stop 4 is positioned in the center ofthe diaphragm 2. The central region 21 of the diaphragm 2 is arrangedaround the insert 24. The projections 22, here a total of four, thatserve to guide and center the governor spring 5 in relation to thediaphragm 2 and are pointing in a downward direction, that is towardsthe viewer, can be seen in an even further radially outward direction.

The dashed lines in FIG. 6 a represent the diaphragm supporting body 23which is embedded in the elastomeric material of the diaphragm 2.Therein, the projections 22 and the insert 24 are integral parts of thediaphragm supporting body 23 and designed in one piece therewith.Therein, the insert 24 is in communication with the remaining diaphragmsupporting body 23 via connection webs 25 that are extending along acurved path. This ensures an appropriate elasticity and flexibility ofthe central region 21 of the diaphragm 2, said elasticity andflexibility being necessary for proper functioning of the pressureregulating valve 1.

A third version of the pressure regulating valve 1 is shown in FIGS. 7,8 and 9 in the “open”, “partially closed” and “closed” states. Thisversion of the pressure regulating valve 1 is different from the twoversions of the pressure regulating valve 1 described above in that thepreliminary stop 4 is now displaced out of the pipe connection piece 30and into a position arranged in a radially outward direction from thepipe connection piece 30. In the illustrated instance, the preliminarystop is formed by a total of four pins 40 which are uniformly spacedapart from each other and are arranged around the upper end of the pipeconnection piece 30 and are integrally formed with the casing 10 viaconnection blades 41. Here as well, the upper ends of the pins 40jointly forming the preliminary stop 4 project beyond the upper frontend of the pipe connection piece 30, said upper front end forming thestop 31.

In the open state of the pressure regulating valve 1 shown in FIG. 7,the diaphragm 2 is at its upper end position and has, at its bottomside, lifted off from both the preliminary stop 4 and the stop 31. Thisprovides the maximum possible flow cross-section through the pressureregulating valve 1.

In the partially closed position of the pressure regulating valve 1shown in FIG. 8, the diaphragm 2 is displaced in downward direction andnow bears against the preliminary stop 4 at its bottom side. Now, theavailable flow cross-section through the pressure regulating valve 1 isreduced.

In FIG. 9, the control diaphragm 2 has moved further in downwarddirection so that, now, the bottom side of the diaphragm 2 bears notonly against the preliminary stop 4 but, at the same time, also againstthe stop 31. As is clearly illustrated in FIG. 9, this requires anelastic and flexible deformation of the central region 21 of thediaphragm 2. Hence, this shows that, in order to achieve a furtheradjustment of the diaphragm 2 from a position where it only bearsagainst the preliminary stop 4 to a position where the bottom side ofthe diaphragm 2 also bears against the stop 31, an additional adjustingforce or an adjusting force that is different from that having to beexerted for the first part of the travel distance of the controldiaphragm 2 must be exerted.

In its function and also in its remaining component parts, the pressureregulating according to FIGS. 7 to 9 corresponds to the versionsdescribed above, while reference to the above description is made withregard to the further component parts of the pressure regulating valve 1according to FIGS. 7 to 9.

FIGS. 10 to 12 show a forth version of the pressure regulating valve 1.In this version of the pressure regulating valve 1, the preliminary stop4 is formed by an annular region of the casing 10, said region pointingin upward direction. This region forming the preliminary stop 4 ispositioned opposite to the projections 22 protruding out of the bottomside of the control diaphragm 2 in downward direction.

In the completely open state of the pressure regulating valve 1 shown inFIG. 10, the diaphragm 2 has reached its upper position and the downwardprojections 22 are spaced apart from the preliminary stop 4.

In the partially closed state of the pressure regulating valve 1 shownin FIG. 11, a differential pressure has caused a downward movement ofthe diaphragm 2 until the lower front ends of the projections 22 comeinto bearing against the preliminary stop 4.

FIG. 12 shows the closed state of the pressure regulating valve 1 ofFIG. 11 wherein, now, the central region 21 of the diaphragm 2 has beenfurther deformed in an elastic and flexible manner and has, thus, movedin downward direction to a position where its bottom side also bearsagainst the stop 31 at the upper end of the pipe connection piece 30.

In the pressure regulating valve 1 according to FIGS. 10 to 12, theadjustment of the diaphragm 2 in its closing direction from the upperposition of the diaphragm to the position where the projections 22contact the preliminary stop 4 is effected only against the force of thegovernor spring 5. To be further adjusted, the diaphragm 2 must, initself, be additionally deformed in its central region 21 in an elasticand flexible manner; this requires a higher force than is necessary formerely adjusting against the return force of the governor spring 5. As aresult, this allows manipulation of the control characteristic of thepressure regulating valve 1 here as well, thus preventing any prematureand undesired complete closing of the pressure regulating valve 1.

In each of the pressure regulating valves 1 described above by way ofexample, the control diaphragm 2 itself is the element of the pressureregulating valve 1 that, as a closing element, cooperates with the pipeconnection piece 30 and the outflow cross-section 3 extendingtherethrough. In the version of the pressure regulating valve 1according to FIGS. 13 to 15, a separate closing element 2′ is nowprovided as opposed to the previous versions. In the illustratedinstance, this separate closing element 2′ is designed like a stamp witha lower disk-shaped part the diameter of which slightly exceeds theclear diameter of the outflow cross-section 3. At its bottom side, theclosing element 2′ is provided with an elastomeric lining 26′. Theclosing element 2′ is formed integrally with the diaphragm supportingbody 23 and the insert 24 forming a part thereof via a stem-shapedconnection element 24′.

Here as well, a pin 40 the upper end of which projects beyond the upperend of the pipe connection piece 30 and forms the preliminary stop 4 isarranged centrally in the pipe connection piece 30.

In the open state shown in FIG. 13, the diaphragm 2 is arranged in itsupper position and the closing element 2′ has lifted off in upwarddirection from the preliminary stop 4 and the stop 31 by the maximumpossible distance. Hence, the pressure regulating valve 1 now has itsmaximum free flow cross-section.

FIG. 14 shows the pressure regulating valve 1 of FIG. 13 in a partiallyclosed state. Here, an appropriate differential pressure has moved thecontrol diaphragm 2 in downward direction to a position where the bottomside of the elastomeric lining 26′ of the closing element 2′ bearsagainst the preliminary stop 4, however not against the stop 31. Hence,the flow cross-section 3 that is now available through the pressureregulating valve 1 is reduced.

FIG. 15 shows the pressure regulating valve 1 of FIGS. 13 and 14 in itscompletely closed state. Here, an increasing differential pressure hasmoved the control diaphragm 2 even further in downward direction. As aresult, the elastomeric lining 26′ is compressed in the region where itcontacts the preliminary stop 4, until the radially outward region ofthe elastomeric lining 26′ of the closing element 2′ bears against thestop 31. As a result, the flow cross-section of the pressure regulatingvalve 1 is now closed.

In this version of the pressure regulating valve 1 as well, theadjusting motion of the control diaphragm 2 in the first adjustmentrange between the completely open position and that position where theelastomeric lining 26′ of the closing element 2′ comes into bearingagainst the preliminary stop 4 is effected only and exclusively againstthe force of the governor spring 5. To ensure further adjustment, theelastic return force of the elastomeric lining 26′ of the closingelement 2′ must be overcome in addition to the force of the governorspring 5.

Hence, the pressure regulating valve 1 according to FIGS. 13 to 15 alsoachieves a control characteristic which prevents any undesired andpremature complete closing of the pressure regulating valve 1.

In its remaining component parts, the pressure regulating valve 1according to FIGS. 13 to 15 corresponds to the pressure regulating valveaccording to FIGS. 1 to 3, with reference being made to the latter'sdescription.

FIG. 16 shows a pressure diagram illustrating the effect of the pressureregulating valves 1 described above as compared with a conventionalpressure regulating valve. In the pressure diagram, the outflow-sidepressure in the lower chamber 13 is opposed against the inflow-sidepressure in the gas inlet 11. The dash-dotted line represents thereference pressure, e.g. the ambient or atmospheric pressure, in the gasinlet 11.

The dashed line shows a typical control behavior of a conventionalpressure regulating valve. With the pressure in the lower chamber 13decreasing, the pressure in the gas inlet 11 initially decreasesrapidly. Thereafter, however, the pressure in the gas inlet 11 steadilyrises again while the pressure in the lower chamber 13 furtherdecreases. This rise in pressure in the gas inlet 11 with decreasingpressure in the lower chamber 13 is not desired in many applications.

In such cases, the pressure regulating valve 1 according to theinvention is a remedy a typical control characteristic of which isrepresented by the continuous line. Here as well, the pressure in thegas inlet 11 rapidly drops as the pressure in the lower chamber 13decreases. After a specific vacuum pressure has been reached in the gasinlet 11, the pressure in the gas inlet 11 is, however, kept at aconstant level, even if the outflow-side pressure in the lower chamber13 decreases further. The pressure regulating valve 1 according to theinvention reliably prevents the development of any high, disturbing oreven harmful pressure on the inflow side in the gas inlet 11.

FIGS. 17 and 18 show two modifications of the pressure regulating valve1 of FIGS. 1 to 3.

The pressure regulating valve 1 according to FIG. 17 provides in thecentral region 21 of the control diaphragm 2 a weakening of the materialon the upper side, said weakening altering the elastic and flexibleproperties of the control diaphragm 2 in this region. In this executiveform, the diaphragm 2 can, in particular, be deformed in its centralregion 21 with only low efforts.

Contrary thereto, the control diaphragm in the pressure regulating valve1 according to FIG. 18 comprises a thickening of the material in itscentral region 21. As a result, increased efforts are required forfurther deforming the central region 21 of the diaphragm 2. Using thesetwo measures, the efforts for further adjusting the diaphragm 2 from theposition where it bears against the preliminary stop 4 to the positionwhere it bears against the stop 31 can be altered in differentdirections.

In addition or as an alternative thereto, it is also possible to makethe positions of the preliminary stop 4 and the stop 31 adjustable inrelation to each other. This measure can also be used to manipulate theefforts required for further adjusting the control diaphragm 2, with theresult that the control characteristic of the pressure regulating valve1 is manipulated accordingly.

In their further component parts that have not been illustrated above,the pressure regulating valves 1 according to FIGS. 17 and 18 correspondto the pressure regulating valve according to FIGS. 1 to 3.

FIG. 19 shows an eighth version of the pressure regulating valve 1. Inthis version, which is comparable to the forth version of the pressureregulating valve 1 according to FIGS. 10 to 12, the preliminary stop 4is provided on the upper side of a lower wall of the casing 10, here inthe form of an annular elevation extending around the pipe connectionpiece 30 and resembling the shape of a bead.

Here, the control diaphragm 2 is designed with an integrated diaphragmsupporting body 23, from which projections 22 are again protruding indownward direction. At their outer surface, said projections 22 areprovided with an elastomeric lining formed integrally with theelastomeric material from which the diaphragm 2 is made predominantly.

In the partially closed state of the pressure regulating valve 1 shownin FIG. 19, the projections 22 bear against the preliminary stop 4 withtheir lower front end. Here, the central region 21 of the diaphragm 2 isstill spaced apart from the stop 31 at the upper front end of the pipeconnection piece 30.

In order to put this pressure regulating valve 1 in its completelyclosed position, the central region 21 of the control diaphragm 2 mustbe elastically and flexibly deformed in downward direction until thebottom side of the central region 21 of the diaphragm 2 bears againstthe stop 31. Hence, it is, here as well, possible to generate differentcounterforces for the first section of the travel distance of thediaphragm 2 and for the second section of the travel distance of thediaphragm 2, thereby facilitating an appropriate and selectivemanipulation of the control characteristic of the pressure regulatingvalve 1. In its further component parts, the pressure regulating valve 1according to FIG. 19 corresponds to the pressure regulating valveaccording to FIGS. 10 to 12.

In the executive forms of the pressure regulating valve described above,the control diaphragm 2 and its supporting body 23 are made as anintegral injection-molded part. Therein, a prefabricated supporting body23 is coated with the elastic and flexible diaphragm material in ainjection mold during production. As a result, the diaphragm supportingbody 23 is embedded in the elastic and flexible diaphragm material inthe regions provided to that end.

FIG. 20 shows a further exemplary embodiment of the pressure regulatingvalve 1 which differs from the pressure regulating valve described abovewith regard to the design and the manufacture of the control diaphragm 2and its supporting body 23. In the pressure regulating valve 1 accordingto FIG. 20, the diaphragm supporting body 23 and the remaining, elasticand flexible part of the control diaphragm 2 are component parts, hereinjection-molded parts, that are initially manufactured separately.After having been manufactured, these two parts 2, 23 are connected toeach other, in order to form the complete component comprising thecontrol diaphragm 2 and the associated diaphragm supporting body 23,which is visible in FIG. 20.

In order to connect the diaphragm supporting body 23 to the remainingcontrol diaphragm 2, the latter comprises in its central region aprojection with a circumferential groove-shaped undercut 26 that is openin a radially outward direction, said projection pointing in downwarddirection, that is towards the supporting body 23. Here, the diaphragmsupporting body 23 is designed in the form of a ring, that is with acentral breakthrough. The central region of the control diaphragm 2 thatis made of the elastic and flexible material and is projecting indownward direction can be pressed through said breakthrough undercompression, until the radially inward edge of the diaphragm supportingbody 23 is positioned in the undercut 26. In this state, the diaphragmsupporting body 23 and the remaining control diaphragm 2 are thenconnected to each other in an appropriately firm and permanent manner.

At its upper end, the governor spring 5 is supported against the bottomside of the diaphragm supporting body 23 that is, in turn, arrangedunderneath the elastic and flexible control diaphragm 2. As is the casein the exemplary embodiment of the pressure regulating valve 1 accordingto FIGS. 1 to 3, a central pin 40 the upper end of which forms apreliminary stop 4 for the control diaphragm 2 and which projects beyondthe stop 31 at the upper end of the pipe connection piece 30 surroundingthe outflow cross-section 3 is also arranged in the exemplary embodimentaccording to FIG. 20.

FIG. 20 shows the pressure regulating valve 1 in its partially closedstate where the control diaphragm 2 just bears against the preliminarystop 4 with its central region. Before it has reached this position, thecontrol diaphragm 2 had to overcome only the force of the governorspring 5, when it was moved out of its completely open position inclosing direction. Here as well, the force for this adjustment isproduced by a specific vacuum pressure in the lower chamber 13 of thecasing 10, that is a pressure that is lower than the reference pressure,here the atmospheric pressure, in the upper chamber 14.

With increasing vacuum pressure in the lower chamber 13, the centralregion of the control diaphragm 2 deforms in an elastic and flexiblemanner in a radially outward direction of the preliminary stop 4 until,finally, the bottom side of the control diaphragm 2 also comes intobearing against the stop 31. In this position of the control diaphragm2, the pressure regulating valve 1 is closed completely. For this secondpart of the movement of the control diaphragm 2, the elastic andflexible return force of the central region of the control diaphragm 2must be overcome in addition to the force of the governor spring 5, withthe result that the control characteristic is changed as compared to thefirst adjustment range of the control diaphragm 2 from the completelyopen position to the partially closed position.

In its remaining parts and in its function, the pressure regulatingvalve 1 according to FIG. 20 corresponds to the exemplary embodiment ofthe pressure regulating valve 1 according to FIGS. 1 to 3.

In the exemplary embodiment of the pressure regulating valve 1 accordingto FIG. 21, the diaphragm supporting body 23 and the remaining controldiaphragm 2 are again initially manufactured as separate componentparts. In its central region, the elastic and flexible control diaphragm2 possesses a projection 26″ that is pointing in downward direction,that is towards the stop 31, but does not comprise an undercut, asopposed to the executive form according to FIG. 20. With this projection26″, the control diaphragm 2 projects through a central breakthrough inthe diaphragm supporting body 23 that is annular here as well. With itsupper end, the governor spring 5 is supported against the bottom side ofthe diaphragm supporting body 23 from below. In this manner, thediaphragm supporting body 23 is always retained in its bearing positionagainst the bottom side of the control diaphragm 2 without a separateconnection being provided between the diaphragm supporting body 23 andthe remaining control diaphragm 2. The bearing of the diaphragmsupporting body 23 against the bottom side of the control diaphragm 2 ispreserved with each movement of the control diaphragm 2 in upward ordownward direction, because the upper end of the governor spring 5follows each adjusting motion of the control diaphragm 2.

In its remaining component parts and functions, the pressure regulatingvalve 1 according to FIG. 21 corresponds to the pressure regulatingvalve 1 according to FIGS. 1 to 3.

A further exemplary embodiment of a pressure regulating valve 1 is shownin FIG. 22. In this exemplary embodiment, the control diaphragm 2 andthe diaphragm supporting body 23 are designed in the same manner as inthe exemplary embodiment according to FIG. 21.

In its upper region, the pin 40 which is arranged concentrically in theoutflow cross-section 3 and the upper end of which forms the preliminarystop 4 comprises a design that is different from the exemplaryembodiments described above. Here, the pin 40 possesses in its upper endregion a tapered outer contour, wherein the diameter of the pin 40becomes smaller from top to bottom, that is as seen in the flowdirection of the gas through the outflow cross-section 3. Here, thepreliminary stop 4 is designed in the shape of a lens with a rounded capat its side facing the control diaphragm 2.

The contour of the pin 40 shown in FIG. 22 ensures an improved flow pathwhen the gas flows out of the chamber 13, through the passage betweenthe control diaphragm 2 and the stop 31 and into the outflowcross-section 3. Therein, the contour of the pin 40 becomes toparticular advantage for the gas flow when the pressure regulating valve1, as shown in FIG. 22, is in its partially closed position. Here, thecontour of the pin 40 ensures a favorable flow path and redirection ofthe gas flow that is initially extending in radial direction fromwithout inward and then in axially downward direction.

In its further component parts and functions, the pressure regulatingvalve 1 according to FIG. 22 corresponds to the exemplary embodimentaccording to FIG. 21 and to the exemplary embodiment according to FIGS.1 and 3.

FIG. 23 shows a further exemplary embodiment of a pressure regulatingvalve 1 comprising a casing 10 that is closed with a cover 10′ at itstop. An elastic and flexible control diaphragm 2 is, in a sealingmanner, fixed between the casing 10 and the cover 10′ by means of afixing edge 20.

The control diaphragm 2 subdivides the interior region of the casing 10in a lower chamber 13 and an upper chamber 14. The lower chamber 13 isconnected to a gas inlet 11 which is, in turn, connected to the sourceof a gas flow, for example the crankcase of an internal combustionengine. The upper chamber 14 is in communication with the freeatmosphere via a small duct 14′.

Furthermore, an outflow cross-section 3 formed by a short pipeconnection piece 30 comes out of the lower chamber 13, wherein the upperfront face of said pipe connection piece 30 forms a stop 31 for thecontrol diaphragm 2 when the control diaphragm 2 completely closes theoutflow cross-section 3. In the operating state of the pressureregulating valve 1 shown in FIG. 23, the control diaphragm 2 is spacedapart from the stop 31, so that the gas flow passing through the gasinlet 11 and into the chamber 13 can flow out through the outflowcross-section 3 and, thereafter, through the gas outlet 12. For example,the gas outlet 12 is connected to the intake section of an associatedinternal combustion engine.

A governor spring 5 having the form of a helical spring surrounding thepipe connection piece 30 and preloading the control diaphragm 2 with aforce that is acting in upward, i.e. in opening direction, is arrangedbetween the bottom side of the control diaphragm 2 and a surface of thecasing 10 that is pointing in upward direction.

As is furthermore shown in FIG. 23, a preliminary stop 4 the upper edgeof which is positioned at the level of the stop 31 and which is, here,formed by a preliminary stop structure 42 is arranged in the pipeconnection piece 30. This preliminary stop structure 42 comprisesbreakthroughs 43 that are extending in parallel to each other in axialdirection of the outflow cross-section 3, wherein the breakthroughs 43each form a small duct.

Within the control diaphragm 2, only an elastomeric material that iselastic and flexible is provided in the central region 21 of saidcontrol diaphragm 2. Here, a diaphragm supporting body 23 is arranged ina radially outward direction of the central region 21 in the controldiaphragm 2, said diaphragm supporting body 23 comprising a plurality ofprojections 22 that are pointing in downward direction and aredistributed along its perimeter. These projections 22 serve to centerthe upper end of the governor spring 5 in relation to the controldiaphragm 2.

During operation of the pressure regulating valve 1, differentialpressures between a lower pressure in the lower chamber 13 and a higher,here atmospheric, pressure in the upper chamber 14 cause an adjustmentand, at the same time, also a deformation of the control diaphragm 2.Therein, a convex diaphragm region that is pointing in downwarddirection is forming, in particular in the central region 21 of thecontrol diaphragm 2. When the control diaphragm 2 moves in closingdirection, that is in downward direction and towards the pipe connectionpiece 30 in the illustrated instance, the central region 21 of thecontrol diaphragm 2 will, as a result, initially bear against thecentral region of the preliminary stop structure 42, while the diaphragm2 is still spaced apart from the preliminary stop structure 42 and thestop 31 in a radially outward direction of the already bearing diaphragmregion. Only when the pressure in the lower chamber 13 decreasesfurther, will the control diaphragm 2, progressing from within outwardin radial direction, initially bear against the preliminary stopstructure 42 in an increasing manner and finally against the stop 31 aswell.

This process is illustrated in FIGS. 23 a to 23 d with various positionsof the control diaphragm 2. Therein, each of these figures only show adetail of the control diaphragm 2 together with the outflowcross-section 3.

FIG. 23 a shows the control diaphragm 2 in its completely open positionwhere it is spaced apart from the stop 31 and the preliminary stop 4arranged therein as far as possible. Here, the control diaphragm 2possesses a central region 21 which is designed with a convex camberthat is pointing in downward direction, i.e. towards the outflowcross-section 3.

The left-hand and right-hand sections of FIGS. 23 a to 23 d each showtwo different executive forms of the outflow cross-section 3 and thepreliminary stop 4. In each right-hand section, the pipe connectionpiece 30 is, at its upper end, that is at the level of the stop 31,integrally formed with the preliminary stop structure 42 forming thepreliminary stop 4. Here, the preliminary stop structure 42 is formed bywebs that are extending in parallel to each other and perpendicularly tothe drawing plane and leave breakthroughs 43 between each other.

In each left-hand section, a two-piece executive form is shown, whereina sleeve part 48 provided as a separate component part is fitted ontothe pipe connection piece 30, with a sealing ring 48′ being placedintermediately. The upper region of the sleeve part 48 forms the stop 31and, at the same time, also the preliminary stop 4 with the preliminarystop structure 42. Here as well, the preliminary stop structure 42consists of webs or walls which are extending in parallel to each otherand perpendicularly to the drawing plane but which, here, comprise agreater axial length than in the preliminary stop structure 42 in eachof the right-hand sections. In each of the left-hand sections,breakthroughs 43 for the gas flow path are kept free between the wallsforming the preliminary stop structure 42.

In the state shown in FIG. 23 a, the complete flow cross-section throughall breakthroughs 43 in the preliminary stop structure 42 is available.

In the state shown in FIG. 23 b, the control diaphragm 2, owing todifferent pressure conditions below and above the control diaphragm 2,has approached the preliminary stop 4, wherein a first contact betweenthe control diaphragm 2 and the preliminary stop structure 42 is justoccurring in the center of the central region 21 of the controldiaphragm 2. As a result, the flow cross-section through the preliminarystop 4 has already been reduced a little.

As shown in FIG. 23 c, the control diaphragm 2 has moved even further inthe direction of the preliminary stop 4 wherein, starting from itscenter and progressing in a radially outward direction, the centralregion 21 of the control diaphragm 2 has further borne against thepreliminary stop 4 and now closes a part of the breakthroughs 43,whereas the radially outward breakthroughs 43 are still clear. Owing toits elasticity and flexibility, the central region 21 of the controldiaphragm 2 is, therein, bearing against the surface of the preliminarystop structure 42, which is flat in the illustrated instance. In thismanner, a part of the force acting on the diaphragm 2, that is the partof the force that acts in the surface region that is already bearingagainst the preliminary stop structure 42, is diverted directly onto thepipe connection piece 30 and, thus, onto the casing 10 of the pressureregulating valve 1. This promotes a desired control characteristic ofthe pressure regulating valve 1, which is unaffected by the vacuumpressure in the gas outlet to a large extent.

In FIG. 23 d, the control diaphragm 2 is now fully bearing against thepreliminary stop structure 4 and the stop 31 of the outflowcross-section 3, with the result that the closed position where there isno gas flow any longer has been reached.

FIG. 24 shows a second pressure regulating valve 1 which, in contrast tothe example according to FIG. 23, is now additionally provided with aliquid collection chamber 15.

The liquid collection chamber 15 comprises a grid-shaped insert 15.4which prevents the separated liquid from splashing and being entrainedinto the gas outlet piece 12.

Here as well, the casing 10 is provided with a cover 10′ that retainsthe control diaphragm 2 in the casing 10 by means of a fixing edge 20 ina sealing manner. Here as well, the diaphragm 2 subdivides the interiorregion of the casing 10 in a lower chamber 13 and an upper chamber 14.The lower chamber 13 is in communication with the gas inlet 11. Theupper chamber 14 is in communication with the free atmosphere via asmall hole 14′.

Here as well, the central region 21 of the control diaphragm 2 is madeof an elastic and flexible material, such as an elastomer. In a radiallyoutward direction from the central region 21, an annular diaphragmsupporting body 23 serving to center and support the upper end of thegovernor spring 5 is arranged in the control diaphragm 2.

Here as well, a pipe connection piece 30 enclosing an outflowcross-section 3 is arranged in the lower chamber 13. The upper front endof the pipe connection piece 30 forms a stop 31 for the controldiaphragm here as well.

Here as well, a preliminary stop 4 again formed by a preliminary stopstructure 42 practically extending along the entire axial length of theoutflow cross-section 3 is arranged in the outflow cross-section 3. Hereas well, the preliminary stop structure 42 comprises a plurality ofductlike breakthroughs 43 that are extending in parallel to each otherand in the axial direction of the outflow cross-section 3.

The lower part of the casing is occupied by the liquid collectionchamber 15 the lower part of which forms a liquid collection region 15′.The upper part of the liquid collection chamber 15 serves to separategas from liquid. Liquid particles carried along in the gas, e.g. oilmist or oil droplets, are separated in the region of the preliminarystop structure 42, caused by the sharp change in direction that isinevitably occurring when the gas flows out of the lower chamber 13,passes underneath the control diaphragm 2 and flows into thebreakthroughs 43. Owing to inertia, this sharp redirection causes theentrained liquid droplets to impinge on the preliminary stop structure42 delimiting the ductlike breakthroughs 43. The settled liquid followsgravity and the gas flow in downward direction and flows via a gas inlet15.1 and into the liquid collection chamber 15. From there, the liquiddrops down and into the liquid collection region 15′. In this exemplaryembodiment, the ductlike breakthroughs 43 have a different axialextension, that means that the geodetically lower end of the ductlikebreakthroughs spreads a plane that extends at an angle in relation tothe horizontal. Therein, the lower front end of the pipe connectionpiece 30 may also be inclined in relation to the central axis of thepipe connection piece. As a result, the settled liquid can beselectively passed to the geodetically bottommost point of the outflowcross-section 3, from where it can drop down into the liquid collectionregion 15′. In this manner, separated oil droplets are prevented frombeing entrained in the flow.

The gas from which the liquid content has been separated flows throughthe cleaned-gas outlet 15.2 to the upper left in the liquid collectionchamber 15 into the gas outlet 12 and from there, for example, into theintake section of an associated internal combustion engine.

Here, a reed valve 16 that is positioned underneath a liquid outlet 15.3serves to discharge the liquid collected from the liquid collectionregion 15′. Appropriately, a line that is not shown here removes theliquid that is flowing out when the valve 16 is open from said liquidoutlet 15.3 and returns it, for example, into the crankcase of anassociated internal combustion engine.

FIG. 24 a is an enlarged detail illustrating the separation of entrainedliquid droplets from the gas flow in the region of the preliminary stop4. At the top in FIG. 24 a, a detail of the control diaphragm 2, here ofits central region 21, can be seen. Therein, the separation mechanism issimilar to that of an impactor.

The pipe connection piece 30 whose upper front side facing the controldiaphragm 2 forms the stop 31 can be seen in the lower part of FIG. 24a.

The preliminary stop 4 that consists of the preliminary stop structure42 comprising the breakthroughs 43 is arranged in the pipe connectionpiece 30.

The dashed lines indicate the flow of a gas carrying liquid droplets andflowing from a radially outward direction, that is from the leftaccording to FIG. 24 a, to the region underneath the control diaphragm 2where it flows into the breakthroughs 43 after having undergone a sharpchange in direction by approximately 90 degrees and then continues itsflow through said breakthroughs in downward direction. As illustrated inthe diagrammatic representation, the liquid droplets carried along inthe gas flow can follow the sharp redirection of the gas when it entersinto the breakthroughs 43 only incompletely, with the result that theliquid droplets impinge on the preliminary stop structure 42 delimitingthe breakthroughs 43. The liquid droplets collect at the preliminarystop structure 42 and, following gravity and the gas flow in thebreakthroughs 43, flow as a liquid film in downward direction.

In this manner, a liquid separation from the gas flowing through thepressure regulating valve 1 is achieved in addition to the pressureregulation in the pressure regulating valve 1, without any complicatedindependent liquid separator.

FIG. 25 is a longitudinal sectional view of a pipe connection piece 30as a component part of a pressure regulating valve. The left-handsection of FIG. 25 shows a preliminary stop structure 42 that isarranged in the outflow cross-section 3 and is relatively short in axialdirection, while the right-hand section of FIG. 25 shows a preliminarystop structure 42 comprising a length that is considerably longer inaxial direction. By selecting the axial length of the preliminary stopstructure and, thus, of the breakthroughs 43, in an appropriate manner,the desired liquid separation from the gas flowing therethrough can bemanipulated and optimized.

FIGS. 25 a to 25 d each are top views of the pipe connection piece 30 invarious executive forms of the preliminary stop 4 and its preliminarystop structure 42.

According to FIG. 25 a, the preliminary stop structure is formed by flatwalls 44.1 that are intersecting each other at right angles, wherein thebreakthroughs 43, having a square cross-section, extend between saidwalls 44.1.

According to FIG. 25 b, the preliminary stop structure 42 also consistsof intersecting flat walls 44.1 wherein here, however, the intersectionangle selected is an acute angle resulting in a rhomboid cross-sectionof the breakthroughs 43.

According to FIG. 25 c, the preliminary stop structure 42 compriseswalls 44.2 extending in radial direction and walls 44.3 extending incircumferential direction, with the breakthroughs 43 being arrangedtherebetween.

FIG. 25 d shows an example of a preliminary stop structure 42 wherewalls 44.2 are provided which are, in essence, extending in radialdirection and are converging in a radially inward ring that is smallerin diameter.

FIGS. 26 a to 26 d show further appropriate executive forms of the pipeconnection piece 30 and the preliminary stop 4 provided therein.

According to FIG. 26 a, the breakthroughs 43 in the preliminary stopstructure 42 are designed with a hexagonal cross-section, resulting in ahoneycomb structure of sorts.

According to FIG. 26 b, the breakthroughs 43 in the preliminary stopstructure 42 are designed as circular holes. This example ischaracteristic in that the pipe connection piece 30 is, here, notcircular, but ovoid in cross-section. This special design also allows tomanipulate the control characteristic of the pressure regulating valve 1in a selective manner.

FIG. 26 c shows two different executive forms to the upper right and thelower left. To the upper right, the breakthroughs 43 are designed ascircular holes all being equal in diameter. To the lower left in FIG. 26c, the breakthroughs 43 are designed as holes that are differing intheir diameters, wherein the diameter becomes smaller from a radiallyinward direction to a radially outward direction. The outer contour ofthe pipe connection piece 30 is again circular in FIG. 26 c.

FIG. 26 d shows an executive form where the pipe connection piece 30 hasan elliptic contour. Here, the breakthroughs 43 in the preliminary stopstructure are again designed as circular holes that are equal in size.

FIGS. 27, 27 a, 27 b, and 27 c again show a pipe connection piece 30with three further executive forms of the preliminary stop structure 42.FIG. 27 is a longitudinal sectional view of the pipe connection piece 30with its stop 31 on the top and with the inserted preliminary stop 4.Here, the preliminary stop structure 42 is again designed with a flatsurface on its top. For that reason, the control diaphragm 2 (not shown)cooperating with said preliminary stop structure 42 should preferably beconvex in shape.

The preliminary stop structure 42 according to FIG. 27 again formsbreakthroughs 43 that are extending in parallel to each other and inaxial direction of the pipe connection piece 30. Here, the preliminarystop structure 42 is formed by a honeycomb 46.

FIG. 27 a and FIG. 27 b are top views of two possible executive forms ofthis honeycomb 46. The honeycomb 46 according to FIG. 27 a is a layeredhoneycomb structure. In the example according to FIG. 27 b, thehoneycomb structure 46 is designed concentrically to the center of thepipe connection piece 30.

FIG. 27 c shows a pipe connection piece 30 with a central core 32 thatis connected to or formed integrally with the pipe connection piece 30via ribs 32.1. A honeycomb 46 is fitted on said central core 32.

FIG. 28 a and FIG. 28 b show a further example of a pipe connectionpiece 30 for the outflow cross-section 3 with the preliminary stop 4.FIG. 28 a is a longitudinal sectional view of the pipe connection piece30 delimiting the outflow cross-section 3. Here, the preliminary stopstructure 42 is arranged in the outflow cross-section 3 along the entirevertical length wherein, in the illustrated instance, the preliminarystop structure 42 is formed by flat walls 45 that extend in parallel toeach other and in parallel to the drawing plane.

FIG. 28 b is a top view of the walls 45 showing their parallelarrangement in a particularly clear manner. A free breakthrough 43 forguiding the gas flow is arranged between every two walls 45.

In the same type of representation as in FIGS. 28 a and 28 b, FIGS. 29 aand 29 b each show a further example of a pipe connection piece 30 forthe outflow cross-section 3 with the preliminary stop 3 providedtherein. This example is characteristic in that the preliminary stopstructure 42 is formed by a plurality of pins 47 extending in parallelto each other and in axial direction of the pipe connection piece 30,said pins 47 being integrally formed with the pipe connection piece 30during production of the latter. For example, such a production isachievable without any problems when thermoplastic material is used.

FIG. 29 b is a top view of the pipe connection piece 30 with thepreliminary stop 4. The parallel pins 47 form the preliminary stopstructure 42, wherein the diaphragm 2 can come into bearing against thesurface of said structure 42, said surface being formed by the free pinends, in the way and manner described above by means of FIGS. 23 a to 23d and to a more or less pronounced degree. Between the pins 47, a freeflow cross-section remains as outflow cross-section 3 for the gas.

FIG. 30 is a partially sectional view of an executive form of a pressureregulating valve in which it is not the control diaphragm 2 itself thatcooperates with the outflow cross-section 3 and the preliminary stop 4provided therein, but a closing element 2′ that is actuated by saidcontrol diaphragm 2.

At its bottom, FIG. 30 shows the upper end region of the pipe connectionpiece 30, which encloses the outflow cross-section 3 and the upper frontside of which forms the stop 31. Here as well, a preliminary stopstructure 42 forming the preliminary stop 4 is arranged in the outflowcross-section 3. Here, said preliminary stop structure 42 consists ofshort webs extending in parallel to each other and perpendicularly tothe drawing plane, with breakthroughs 43 serving to guide the gas beingkept free between said webs.

Here, the closing element 2′ consists of a connection element 24′ thatis enlarged in the form of a plate at its bottom and is connected to thecontrol diaphragm 2 at its upper end that is not visible here. The lowerpart of the closing element 2′ is provided with an elastomeric lining26′ having a convex shape that points in downward direction in theunloaded state. The lining 26′ is elastic and flexible and, onapproaching the preliminary stop 4, initially bears against the latterwith its center. As it approaches further, the lining 26′ thenincreasingly comes into bearing with the preliminary stop 4, progressingfrom within outward in a radial direction, until it is finally alsobearing against the stop 31, thus reaching the closed position.

In the unloaded state of the elastomeric lining 26′ that is shown inFIG. 30, there is a cavity 27′ between the top side of the elastomericlining 26′ and the bottom side of the connection element 24′. In orderto ensure that the gas present in said cavity can escape when theelastomeric lining 26′ approaches and bears against the preliminary stop4, a hole 28′ is provided, said hole 28′ extending from the cavity 27′through the disk-shaped enlarged lower end of the connection element 24′to the latter's top side.

FIG. 30 a shows a modified elastomeric lining 26′. On its side pointingin downward direction, that is to the preliminary stop 4, this secondelastomeric lining 26′ is also convex in its unloaded state. Here aswell, the elastomeric lining 26′ is elastic and flexible but, at thesame time, also compressible. As a result, the cavity 27′ with the hole28′ is not necessary.

FIGS. 31 a and 31 b are a longitudinal sectional view and across-sectional view respectively of a further pressure regulating valve1 provided with a liquid collection chamber 15.

To its upper right, the longitudinal view according to FIG. 31 a showsthe control diaphragm 2 in the casing 10, wherein said control diaphragm2 is, here, arranged in a vertical plane, this being of no irrelevanceto the function of the control diaphragm 2. In this example, the chamber13 that is connected to a gas source via a gas inlet that is not visiblein FIG. 31 a is arranged to the left of the control diaphragm in thecasing 10. The chamber 14 that is connected to the free atmosphere viathe hole 14′ is arranged to the right of the control diaphragm 2. Here,the control diaphragm 2 corresponds to the executive form according toFIG. 23. Here as well, the control diaphragm 2 is subjected to thegovernor spring 5 in opening direction.

In the region bordered by the governor spring 5, the pipe connectionpiece 30 forming the outflow cross-section 3 for the gas that is flowingout of the chamber 13 in a controlled manner is arranged coaxially tosaid governor spring 5. Here as well, a preliminary stop structure, hereconsisting of parallel walls 45 extending perpendicularly to the drawingplane, is arranged in the pipe connection piece 30.

Here as well, the front side of the pipe connection piece 30 facing thecontrol diaphragm 2 forms the stop 31 for the closed position of thecontrol diaphragm 2. The preliminary stop 4 is arranged radially inwardof the stop 31, wherein the control diaphragm, when approaching theoutflow cross-section 3, can come into bearing with said preliminarystop 4, starting radially inward and then progressing in a radiallyoutward direction.

Here, the liquid collection chamber 15 is designed as a liquidseparator; to achieve this, it is circular in shape as is illustrated inthe cross-sectional view shown in FIG. 31 b. The gas flowing out throughthe outflow cross-section 3 flows through a gas inlet 15.1 and thentangentially into the liquid collection chamber 15, thereby causing arotating flow of the gas. By virtue of centrifugal force, said rotatingflow causes entrained liquid droplets to settle on the internal surfaceof the part of the casing 10 that delimits the liquid collection space15. By virtue of gravity, the settled liquid flows in downward directionand collects in the liquid collection chamber 15′. From there, thecollected liquid can be discharged via the liquid outlet 15.3 with thereed valve 16 being open. Internal attachments prevent the separatedliquid from splashing.

The gas exits the liquid collection chamber 15 through a cleaned-gasoutlet 15.2, which is also extending in tangential direction, and thenflows out through the gas outlet 12.

A further example of a pressure regulating valve 1 with integratedliquid collection chamber 15 is shown in FIGS. 32 a and 32 b, whereinFIG. 32 a is a longitudinal sectional view and FIG. 32 b is across-sectional view.

The control diaphragm 2 and the part of the casing 10 accommodating itcorrespond to the executive form according to FIGS. 31 a and 31 b. Here,a honeycomb 46 that is provided as an insert is fitted in the pipeconnection piece 30 delimiting the outflow cross-section 3, saidhoneycomb 46 separating at least a part of the liquid droplets from thegas flowing therethrough, as has already been illustrated above.

As shown particularly clearly in FIG. 32 b, the outflow cross-section 3changes into a tangential gas inlet 15.1 ending in the liquid collectionchamber 15 that is circular in cross-section here as well. The part ofthe casing 10 forming the liquid collection chamber 15 is designed inthe form of a cyclone, in order to allow further liquid separation fromthe gas flow. Owing to the tangential inlet 15.1, the gas flow insidethe liquid collection chamber 15 is forced into a rotatory direction,whereby entrained liquid droplets settle on the internal surface of theliquid collection chamber 15 by virtue of centrifugal force.

The cleaned gas exits the liquid collection chamber 15 that acts as acyclone through a cleaned-gas outlet 15.2 arranged centrally in theupper region of said liquid collection chamber 15 and changing into thegas outlet 12.

By virtue of gravity, the settled liquid flows in downward directioninside the liquid collection chamber 15, through the liquid outlet 15.3and into the liquid collection region 15′. Here as well, internalattachments may be provided in order to prevent the separated liquidfrom splashing Via a reed valve 16, the collected liquid can bedischarged through a further liquid outlet 15.3′ arranged at thebottommost point of the liquid collection region 15′. In order toprevent the ducts of the honeycomb 46 from freezing under unfavorableoperating conditions, an electrically heatable heater element, theelectric feeder of which is not shown in the illustrated instance, isarranged around the outflow piece 30.

FIGS. 33 a and 33 b show a further example of a pressure regulatingvalve 1. Therein, FIG. 33 a is a longitudinal sectional view of thearrangement with a preseparator 6 and FIG. 33 b is a cross-sectionalview of said preseparator 6. In this variant, an impingement or lamellarseparator is arranged as preseparator 6 in the gas inlet 11. Saidpreseparator 6 can, to advantage, be provided whenever the gas flowcontains a high concentration of relatively large-size oil droplets. Byarranging the deflecting walls 60 in the gas inlet 11, the coarseportions of the oil mist can be separated in an effective mannerTherein, it can be preferably provided that at least the geodeticallylower wall of the gas inlet duct 11 is inclined in relation to thehorizontal such that any oil droplets having separated in thepreseparator 6 can return into the crankcase counter to the flowdirection.

FIG. 34 is a longitudinal sectional view of a further variant of apreseparator. Here, the preseparator 6 is designed as a screen structure61 arranged concentrically to the pipe connection piece 30′ and, as seenin flow direction, between the gas inlet 11 and the preliminary stop 4.Therein, the pores of the screen structure 61 can be dimensioned suchthat particles from the gas flow which might close the ducts 43 of thepreliminary stop structure are retained.

FIGS. 35 a and 35 b show two further forms of the preliminary stop 4.FIG. 35 a comprises a convex design of the preliminary stop structure42, which can, for example, be to advantage if use is made of a somewhatstiffer diaphragm. In the executive form according to FIG. 35 b, a core32 is arranged centrally in the pipe connection piece 30 of the outflowcross-section 3.

In the tangentially arranged gas inlet 11 according to FIG. 36, the aircolumn is caused to rotate inside the upper chamber 13. When enteringinto the breakthroughs 43 of the preliminary stop structure 42, theresulting gas vortex ensures an optimized separation of the oil dropletscarried along in the gas flow, even if the gaps between the diaphragmand the preliminary stop structure are larger in size.

As is apparent from the foregoing specification, the invention issusceptible of being embodied with various alterations and modificationswhich may differ particularly from those that have been described in thepreceding specification and description. It should be understood that wewish to embody within the scope of the patent warranted hereon all suchmodifications as reasonably and properly come within the scope of ourcontribution to the art.

1. A pneumatic crankcase pressure regulating valve for regulating gaspressure in a crankcase of an internal combustion engine, the pressureregulating valve being arranged in the path of a crankcase ventilationline and having an opening which can be automatically changed by meansof the pressure regulating valve in relation to a differential pressurebetween a reference pressure and one or more gas pressures applied to atleast one inlet of the pressure regulating valve, comprising a controldiaphragm including a closing element located in the pressure regulatingvalve, the control diaphragm being subjected to the reference pressureon one side thereof and being subjected to the gas pressure as well asto a governor spring on an opposite side, wherein a change in thedifferential pressure between regions adjacent to the control diaphragmcauses an adjustment of the control diaphragm in the form of a movementof the control diagram, and the movement of the control diaphragmincreases or reduces an outflow cross-section of the valve opening, astructure of the pressure regulating valve arranged adjacent to theoutflow cross-section on the diaphragm side to form a valve seat stopfor the closing element of the control diaphragm in a closed position ofthe control diaphragm, a preliminary stop in the form of a plurality ofrigid, non-elastic and non-flexible preliminary stop pins arranged inthe pressure regulating valve radially outwardly of the valve seat stopsuch that, when the control diaphragm is moving in its closingdirection, the control diaphragm first comes into contact with thepreliminary stop pins, the control diaphragm having at least a portionthat is formed of an elastomeric material that is elastic and flexible,such that when the control diaphragm is moving further in its closingdirection, the control diaphragm will then, while being subjected toelastic and flexible deformation, further reduce the cross-section ofthe valve opening and, in a final position, also come into contact withthe valve seat stop.
 2. A pressure regulating valve according to claim1, wherein the preliminary stop is formed by a circle of pins arrangedconcentrically to the stop.
 3. A pressure regulating valve according toclaim 1, wherein the preliminary stop pins are uniformly spaced apartfrom each other.
 4. A pressure regulating valve according to claim 1,wherein the pressure regulating valve comprises a casing that is closedwith a cover, the control diaphragm being fixed between the casing andthe cover, and the preliminary stop pins are integrally formed with thecasing.
 5. A pressure regulating valve according to claim 4, wherein thepreliminary stop pins are integrally formed with the casing viaconnection blades.
 6. A pressure regulating valve according to claim 1,wherein the preliminary stop is formed by four preliminary stop pins. 7.A pressure regulating valve according to claim 1, wherein thepreliminary stop pins project beyond the valve seat stop towards thediaphragm.
 8. A pressure regulating valve according to claim 1, whereinthe preliminary stop is in the form of at least a segment of a ring. 9.A pneumatic crankcase pressure regulating valve for regulating gaspressure in a crankcase of an internal combustion engine, the pressureregulating valve being arranged in the path of a crankcase ventilationline and having an opening which can be automatically changed by meansof the pressure regulating valve in relation to a differential pressurebetween a reference pressure and one or more gas pressures applied to atleast one inlet of the pressure regulating valve, comprising a controldiaphragm including a closing element located in the pressure regulatingvalve, the control diaphragm being subjected to the reference pressureon one side thereof and being subjected to the gas pressure as well asto a governor spring on an opposite side, wherein a change in thedifferential pressure between regions adjacent to the control diaphragmcauses an adjustment of the control diaphragm in the form of a movementof the control diagram, and the movement of the control diaphragmincreases or reduces an outflow cross-section of the valve opening, astructure of the pressure regulating valve arranged adjacent to theoutflow cross-section on the diaphragm side to form a valve seat stopfor the closing element of the control diaphragm in a closed position ofthe control diaphragm, a preliminary stop comprising a circulararrangement of a plurality of rigid, non-elastic and non-flexiblepreliminary stop pins in the pressure regulating valve positionedradially outwardly of the valve seat stop such that, when the controldiaphragm is moving in its closing direction, the control diaphragmfirst comes into contact with the preliminary stop pins, the controldiaphragm having at least a portion that is formed of an elastomericmaterial that is elastic and flexible, such that when the controldiaphragm is moving further in its closing direction, the controldiaphragm will then, while being subjected to elastic and flexibledeformation, further reduce the cross-section of the valve opening and,in a final position, also come into contact with the valve seat stop.10. A pressure regulating valve according to claim 9, wherein thepreliminary stop pins are uniformly spaced apart from each other.
 11. Apressure regulating valve according to claim 9, wherein the pressureregulating valve comprises a casing that is closed with a cover, thecontrol diaphragm being fixed between the casing and the cover, and thepreliminary stop pins are integrally formed with the casing.
 12. Apressure regulating valve according to claim 11, wherein the preliminarystop pins are integrally formed with the casing via connection blades.13. A pressure regulating valve according to claim 9, wherein thepreliminary stop is formed by four preliminary stop pins.
 14. A pressureregulating valve according to claim 9, wherein the preliminary stop pinsproject beyond the valve seat stop towards the diaphragm.
 15. Apneumatic crankcase pressure regulating valve for regulating gaspressure in a crankcase of an internal combustion engine, the pressureregulating valve being arranged in the path of a crankcase ventilationline and having an opening which can be automatically changed by meansof the pressure regulating valve in relation to a differential pressurebetween a reference pressure and one or more gas pressures applied to atleast one inlet of the pressure regulating valve, comprising a controldiaphragm including a closing element located in the pressure regulatingvalve, the control diaphragm being subjected to the reference pressureon one side thereof and being subjected to the gas pressure as well asto a governor spring on an opposite side, wherein a change in thedifferential pressure between regions adjacent to the control diaphragmcauses an adjustment of the control diaphragm in the form of a movementof the control diagram, and the movement of the control diaphragmincreases or reduces an outflow cross-section of the valve opening, astructure of the pressure regulating valve arranged adjacent to theoutflow cross-section on the diaphragm side to form a valve seat stopfor the closing element of the control diaphragm in a closed position ofthe control diaphragm, a preliminary stop comprising a plurality ofrigid, non-elastic and non-flexible preliminary stop ring segments inthe pressure regulating valve positioned radially outwardly of the valveseat stop such that, when the control diaphragm is moving in its closingdirection, the control diaphragm first comes into contact with thepreliminary stop ring segments, the control diaphragm having at least aportion that is formed of an elastomeric material that is elastic andflexible, such that when the control diaphragm is moving further in itsclosing direction, the control diaphragm will then, while beingsubjected to elastic and flexible deformation, further reduce thecross-section of the valve opening and, in a final position, also comeinto contact with the valve seat stop.
 16. A pressure regulating valveaccording to claim 15, wherein the preliminary stop ring segments areuniformly spaced apart from each other.
 17. A pressure regulating valveaccording to claim 15, wherein the pressure regulating valve comprises acasing that is closed with a cover, the control diaphragm being fixedbetween the casing and the cover, and the preliminary stop ring segmentsare integrally formed with the casing.
 18. A pressure regulating valveaccording to claim 17, wherein the preliminary stop ring segments areintegrally formed with the casing via connection blades.
 19. A pressureregulating valve according to claim 15, wherein the preliminary stop isformed by four preliminary stop ring segments.
 20. A pressure regulatingvalve according to claim 15, wherein the preliminary stop ring segmentsproject beyond the valve seat stop towards the diaphragm.